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            (<a href="DB.txt">source</a>,
            <a href="https://metacpan.org/pod/DB">CPAN</a>)
          </div>
            <div id="moduleversion">version 1.08</div>
        </div>
        <div class="leading-notice">
          You are viewing the version of this documentation from Perl 5.35.0.
            This is a development version of Perl.
        </div>
        <h1><a id="toc">CONTENTS</a></h1>
                  <ul>
              <li>
                <a class="text-decoration-none" href="DB.html#NAME">NAME</a>
              </li>
              <li>
                <a class="text-decoration-none" href="DB.html#SYNOPSIS">SYNOPSIS</a>
              </li>
              <li>
                <a class="text-decoration-none" href="DB.html#DESCRIPTION">DESCRIPTION</a>
                            <ul>
              <li>
                <a class="text-decoration-none" href="DB.html#Global-Variables">Global Variables</a>
              </li>
              <li>
                <a class="text-decoration-none" href="DB.html#API-Methods">API Methods</a>
              </li>
              <li>
                <a class="text-decoration-none" href="DB.html#Client-Callback-Methods">Client Callback Methods</a>
              </li>
          </ul>

              </li>
              <li>
                <a class="text-decoration-none" href="DB.html#BUGS">BUGS</a>
              </li>
              <li>
                <a class="text-decoration-none" href="DB.html#AUTHOR">AUTHOR</a>
              </li>
          </ul>

      <h1 id="NAME"><a class="permalink" href="DB.html#NAME">#</a>NAME</h1>

<p>DB - programmatic interface to the Perl debugging API</p>

<h1 id="SYNOPSIS"><a class="permalink" href="DB.html#SYNOPSIS">#</a>SYNOPSIS</h1>

<pre><code>package CLIENT;
use DB;
@ISA = qw(DB);

# these (inherited) methods can be called by the client

CLIENT-&gt;register()      # register a client package name
CLIENT-&gt;done()          # de-register from the debugging API
CLIENT-&gt;skippkg(&#39;hide::hide&#39;)  # ask DB not to stop in this package
CLIENT-&gt;cont([WHERE])       # run some more (until BREAK or 
                            # another breakpointt)
CLIENT-&gt;step()              # single step
CLIENT-&gt;next()              # step over
CLIENT-&gt;ret()               # return from current subroutine
CLIENT-&gt;backtrace()         # return the call stack description
CLIENT-&gt;ready()             # call when client setup is done
CLIENT-&gt;trace_toggle()      # toggle subroutine call trace mode
CLIENT-&gt;subs([SUBS])        # return subroutine information
CLIENT-&gt;files()             # return list of all files known to DB
CLIENT-&gt;lines()             # return lines in currently loaded file
CLIENT-&gt;loadfile(FILE,LINE) # load a file and let other clients know
CLIENT-&gt;lineevents()        # return info on lines with actions
CLIENT-&gt;set_break([WHERE],[COND])
CLIENT-&gt;set_tbreak([WHERE])
CLIENT-&gt;clr_breaks([LIST])
CLIENT-&gt;set_action(WHERE,ACTION)
CLIENT-&gt;clr_actions([LIST])
CLIENT-&gt;evalcode(STRING)  # eval STRING in executing code&#39;s context
CLIENT-&gt;prestop([STRING]) # execute in code context before stopping
CLIENT-&gt;poststop([STRING])# execute in code context before resuming

# These methods will be called at the appropriate times.
# Stub versions provided do nothing.
# None of these can block.

CLIENT-&gt;init()          # called when debug API inits itself
CLIENT-&gt;stop(FILE,LINE) # when execution stops
CLIENT-&gt;idle()          # while stopped (can be a client event loop)
CLIENT-&gt;cleanup()       # just before exit
CLIENT-&gt;output(LIST)    # called to print any output that
                        # the API must show</code></pre>

<h1 id="DESCRIPTION"><a class="permalink" href="DB.html#DESCRIPTION">#</a>DESCRIPTION</h1>

<p>Perl debug information is frequently required not just by debuggers, but also by modules that need some &quot;special&quot; information to do their job properly, like profilers.</p>

<p>This module abstracts and provides all of the hooks into Perl internal debugging functionality, so that various implementations of Perl debuggers (or packages that want to simply get at the &quot;privileged&quot; debugging data) can all benefit from the development of this common code. Currently used by Swat, the perl/Tk GUI debugger.</p>

<p>Note that multiple &quot;front-ends&quot; can latch into this debugging API simultaneously. This is intended to facilitate things like debugging with a command line and GUI at the same time, debugging debuggers etc. [Sounds nice, but this needs some serious support -- GSAR]</p>

<p>In particular, this API does <b>not</b> provide the following functions:</p>

<ul>

<li><p>data display</p>

</li>
<li><p>command processing</p>

</li>
<li><p>command alias management</p>

</li>
<li><p>user interface (tty or graphical)</p>

</li>
</ul>

<p>These are intended to be services performed by the clients of this API.</p>

<p>This module attempts to be squeaky clean w.r.t <code>use strict;</code> and when warnings are enabled.</p>

<h2 id="Global-Variables"><a class="permalink" href="DB.html#Global-Variables">#</a><a id="Global"></a>Global Variables</h2>

<p>The following &quot;public&quot; global names can be read by clients of this API. Beware that these should be considered &quot;readonly&quot;.</p>

<dl>

<dt id="$DB::sub"><a class="permalink" href="DB.html#$DB::sub">#</a><a id="DB::sub"></a>$DB::sub</dt>
<dd>

<p>Name of current executing subroutine.</p>

</dd>
<dt id="%DB::sub"><a class="permalink" href="DB.html#%25DB::sub">#</a><a id="DB::sub1"></a>%DB::sub</dt>
<dd>

<p>The keys of this hash are the names of all the known subroutines. Each value is an encoded string that has the sprintf(3) format <code>(&quot;%s:%d-%d&quot;, filename, fromline, toline)</code>.</p>

</dd>
<dt id="$DB::single"><a class="permalink" href="DB.html#$DB::single">#</a><a id="DB::single"></a>$DB::single</dt>
<dd>

<p>Single-step flag. Will be true if the API will stop at the next statement.</p>

</dd>
<dt id="$DB::signal"><a class="permalink" href="DB.html#$DB::signal">#</a><a id="DB::signal"></a>$DB::signal</dt>
<dd>

<p>Signal flag. Will be set to a true value if a signal was caught. Clients may check for this flag to abort time-consuming operations.</p>

</dd>
<dt id="$DB::trace"><a class="permalink" href="DB.html#$DB::trace">#</a><a id="DB::trace"></a>$DB::trace</dt>
<dd>

<p>This flag is set to true if the API is tracing through subroutine calls.</p>

</dd>
<dt id="@DB::args"><a class="permalink" href="DB.html#@DB::args">#</a><a id="DB::args"></a>@DB::args</dt>
<dd>

<p>Contains the arguments of current subroutine, or the <code>@ARGV</code> array if in the toplevel context.</p>

</dd>
<dt id="@DB::dbline"><a class="permalink" href="DB.html#@DB::dbline">#</a><a id="DB::dbline"></a>@DB::dbline</dt>
<dd>

<p>List of lines in currently loaded file.</p>

</dd>
<dt id="%DB::dbline"><a class="permalink" href="DB.html#%25DB::dbline">#</a><a id="DB::dbline1"></a>%DB::dbline</dt>
<dd>

<p>Actions in current file (keys are line numbers). The values are strings that have the sprintf(3) format <code>(&quot;%s\000%s&quot;, breakcondition, actioncode)</code>.</p>

</dd>
<dt id="$DB::package"><a class="permalink" href="DB.html#$DB::package">#</a><a id="DB::package"></a>$DB::package</dt>
<dd>

<p>Package namespace of currently executing code.</p>

</dd>
<dt id="$DB::filename"><a class="permalink" href="DB.html#$DB::filename">#</a><a id="DB::filename"></a>$DB::filename</dt>
<dd>

<p>Currently loaded filename.</p>

</dd>
<dt id="$DB::subname"><a class="permalink" href="DB.html#$DB::subname">#</a><a id="DB::subname"></a>$DB::subname</dt>
<dd>

<p>Fully qualified name of currently executing subroutine.</p>

</dd>
<dt id="$DB::lineno"><a class="permalink" href="DB.html#$DB::lineno">#</a><a id="DB::lineno"></a>$DB::lineno</dt>
<dd>

<p>Line number that will be executed next.</p>

</dd>
</dl>

<h2 id="API-Methods"><a class="permalink" href="DB.html#API-Methods">#</a><a id="API"></a>API Methods</h2>

<p>The following are methods in the DB base class. A client must access these methods by inheritance (*not* by calling them directly), since the API keeps track of clients through the inheritance mechanism.</p>

<dl>

<dt id="CLIENT-&gt;register()"><a class="permalink" href="DB.html#CLIENT-%3Eregister()">#</a><a id="CLIENT"></a><a id="CLIENT-register"></a>CLIENT-&gt;register()</dt>
<dd>

<p>register a client object/package</p>

</dd>
<dt id="CLIENT-&gt;evalcode(STRING)"><a class="permalink" href="DB.html#CLIENT-%3Eevalcode(STRING)">#</a><a id="CLIENT1"></a><a id="CLIENT-evalcode-STRING"></a>CLIENT-&gt;evalcode(STRING)</dt>
<dd>

<p>eval STRING in executing code context</p>

</dd>
<dt id="CLIENT-&gt;skippkg(&#39;D::hide&#39;)"><a class="permalink" href="DB.html#CLIENT-%3Eskippkg(&#39;D::hide&#39;)">#</a><a id="CLIENT2"></a><a id="CLIENT-skippkg-D::hide"></a>CLIENT-&gt;skippkg(&#39;D::hide&#39;)</dt>
<dd>

<p>ask DB not to stop in these packages</p>

</dd>
<dt id="CLIENT-&gt;run()"><a class="permalink" href="DB.html#CLIENT-%3Erun()">#</a><a id="CLIENT3"></a><a id="CLIENT-run"></a>CLIENT-&gt;run()</dt>
<dd>

<p>run some more (until a breakpt is reached)</p>

</dd>
<dt id="CLIENT-&gt;step()"><a class="permalink" href="DB.html#CLIENT-%3Estep()">#</a><a id="CLIENT4"></a><a id="CLIENT-step"></a>CLIENT-&gt;step()</dt>
<dd>

<p>single step</p>

</dd>
<dt id="CLIENT-&gt;next()"><a class="permalink" href="DB.html#CLIENT-%3Enext()">#</a><a id="CLIENT5"></a><a id="CLIENT-next"></a>CLIENT-&gt;next()</dt>
<dd>

<p>step over</p>

</dd>
<dt id="CLIENT-&gt;done()"><a class="permalink" href="DB.html#CLIENT-%3Edone()">#</a><a id="CLIENT6"></a><a id="CLIENT-done"></a>CLIENT-&gt;done()</dt>
<dd>

<p>de-register from the debugging API</p>

</dd>
</dl>

<h2 id="Client-Callback-Methods"><a class="permalink" href="DB.html#Client-Callback-Methods">#</a><a id="Client"></a>Client Callback Methods</h2>

<p>The following &quot;virtual&quot; methods can be defined by the client. They will be called by the API at appropriate points. Note that unless specified otherwise, the debug API only defines empty, non-functional default versions of these methods.</p>

<dl>

<dt id="CLIENT-&gt;init()"><a class="permalink" href="DB.html#CLIENT-%3Einit()">#</a><a id="CLIENT7"></a><a id="CLIENT-init"></a>CLIENT-&gt;init()</dt>
<dd>

<p>Called after debug API inits itself.</p>

</dd>
<dt id="CLIENT-&gt;prestop([STRING])"><a class="permalink" href="DB.html#CLIENT-%3Eprestop(%5BSTRING%5D)">#</a><a id="CLIENT8"></a><a id="CLIENT-prestop-STRING"></a>CLIENT-&gt;prestop([STRING])</dt>
<dd>

<p>Usually inherited from DB package. If no arguments are passed, returns the prestop action string.</p>

</dd>
<dt id="CLIENT-&gt;stop()"><a class="permalink" href="DB.html#CLIENT-%3Estop()">#</a><a id="CLIENT9"></a><a id="CLIENT-stop"></a>CLIENT-&gt;stop()</dt>
<dd>

<p>Called when execution stops (w/ args file, line).</p>

</dd>
<dt id="CLIENT-&gt;idle()"><a class="permalink" href="DB.html#CLIENT-%3Eidle()">#</a><a id="CLIENT10"></a><a id="CLIENT-idle"></a>CLIENT-&gt;idle()</dt>
<dd>

<p>Called while stopped (can be a client event loop).</p>

</dd>
<dt id="CLIENT-&gt;poststop([STRING])"><a class="permalink" href="DB.html#CLIENT-%3Epoststop(%5BSTRING%5D)">#</a><a id="CLIENT11"></a><a id="CLIENT-poststop-STRING"></a>CLIENT-&gt;poststop([STRING])</dt>
<dd>

<p>Usually inherited from DB package. If no arguments are passed, returns the poststop action string.</p>

</dd>
<dt id="CLIENT-&gt;evalcode(STRING)1"><a class="permalink" href="DB.html#CLIENT-%3Eevalcode(STRING)1">#</a><a id="CLIENT12"></a><a id="CLIENT-evalcode-STRING1"></a>CLIENT-&gt;evalcode(STRING)</dt>
<dd>

<p>Usually inherited from DB package. Ask for a STRING to be <code>eval</code>-ed in executing code context.</p>

</dd>
<dt id="CLIENT-&gt;cleanup()"><a class="permalink" href="DB.html#CLIENT-%3Ecleanup()">#</a><a id="CLIENT13"></a><a id="CLIENT-cleanup"></a>CLIENT-&gt;cleanup()</dt>
<dd>

<p>Called just before exit.</p>

</dd>
<dt id="CLIENT-&gt;output(LIST)"><a class="permalink" href="DB.html#CLIENT-%3Eoutput(LIST)">#</a><a id="CLIENT14"></a><a id="CLIENT-output-LIST"></a>CLIENT-&gt;output(LIST)</dt>
<dd>

<p>Called when API must show a message (warnings, errors etc.).</p>

</dd>
</dl>

<h1 id="BUGS"><a class="permalink" href="DB.html#BUGS">#</a>BUGS</h1>

<p>The interface defined by this module is missing some of the later additions to perl&#39;s debugging functionality. As such, this interface should be considered highly experimental and subject to change.</p>

<h1 id="AUTHOR"><a class="permalink" href="DB.html#AUTHOR">#</a>AUTHOR</h1>

<p>Gurusamy Sarathy gsar@activestate.com</p>

<p>This code heavily adapted from an early version of perl5db.pl attributable to Larry Wall and the Perl Porters.</p>


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